tires for an 84 (or speedometer gear replacement)

[grant mills]

Years back I discovered that the standard Michelin tire on my car were too small, causing my speedometer to read 10% too high. I calculated and found a tire size 225-80R15 (Comp T/A) that brought the speedo to an accurate value. But it turned out that this size caused fender rubbing on my front tires as I turned corners (even at slow speeds) I solved this by putting 225-70 on the front. (and I had an additional slight rake to the car which I liked) Now it is time to replace the tires and I can't find the 225-80 anywhere. I would go back to the original sized tire, 215-60R15, if I could replace the gear that drives the speedometer.....but I don't know where or how accessible that gear is. Otherwise I need to find a tire size that will keep my speedo accurate. Any ideas??

[Gunslinger]

Something to check...your front coil springs could be compressed and sagging.  That's a common thing with Avantis with some age.  If that's the case replacing them will cure your tire rubbing issues.

[Dwight FitzSimons]

Assuming that your springs are up to snuff it's probably best to choose your tires appropriately for the car and your driving style, and THEN replace your speedometer gear to match the tire diameter (so the speedo is accurate).  Many with earlier Avantis use 215/70-R15 radials on 6" or 6.5"-wide rims (or 7").  I use 6" or 6.5".  The speedo gear will be in the transmission at the end of the speedo cable.  A transmission shop should be able to replace the speedo gear with the appropriate gear.

--Dwight

Edited April 5, 2023 by Dwight FitzSimons

[grant mills]

My face is red. I blame old age, dim garage, need for glasses.....the tires are actually 225/70 rear, 225/60 front and easily sourced. My confusion arose because (due to some garage being kind and rotating front to rear unbeknownst to me) I was thinking that the 60's were 80's, since I could make out that the front were 70's and I knew that the rear were larger. The reason for the different sizes is still the same, but now it is no longer an issue to source them.